Field of the Invention
The present invention relates to a multilayer ceramic capacitor, a mounting circuit board thereof, and a manufacturing method of the same.
Description of the Related Art
A multilayer ceramic capacitor (MLCC), a multilayer chip electronic component, is capable of being used in various electronic devices, due to advantages such as a small size, high capacitance, ease of mounting, or the like.
For example, the multilayer ceramic capacitor is used in a chip-shaped condenser mounted on circuit boards of various electronic products including display devices such as liquid crystal displays (LCDs), plasma display panels (PDPs) and the like, as well as including computers, smartphones, mobile phones, and the like, to serve to charge and discharge electricity therein.
The multilayer ceramic capacitor may have a structure in which a plurality of dielectric layers and internal electrodes having different polarities are alternately stacked while being interposed between the dielectric layers.
In this case, since the dielectric layers have piezoelectric properties, when a direct current (DC) voltage or an alternating current (AC) voltage is applied to the multilayer ceramic capacitor, a piezoelectric phenomenon may be generated between the internal electrodes, such that a volume of a ceramic body is expanded and contracted according to a frequency, thereby generating periodic vibrations.
The vibrations are transmitted to a circuit board through external electrodes and a solder connecting the external electrodes of the multilayer ceramic capacitor to the circuit board, such that the entire circuit board becomes a sound reflective surface to generate a vibration sound to be a noise.
In this case, the solder connecting the external electrodes and the circuit board is inclined from both side surfaces and both end surfaces of the ceramic body towards surfaces of the external electrodes at a predetermined height, wherein as a volume and the height of the solder become increased, the vibrations of the multilayer ceramic capacitor are easily transmitted to the circuit board, thereby generating a significant amount of vibration sound.
The vibration sound may be in an audible frequency region of 20 to 20,000 Hz, causing listener discomfort, and the vibration sound causing listener discomfort refers to an acoustic noise.
Recently, in electronic devices, since acoustic noise generated in the multilayer ceramic capacitor as described above may be significant due to a decreased noise of components, research into a technology of effectively decreasing the acoustic noise generated in the multilayer ceramic capacitor has been required.
Meanwhile, a method of allowing a length or a width of the external electrode to be smaller than a length or a width of the ceramic body in order to decrease the acoustic noise has been partially disclosed.
However, in this case, since the length of the external electrode is short, equivalent series inductance (ESL) of the multilayer ceramic capacitor may be relatively increased.
In the case in which the ESL of the multilayer ceramic capacitor is increased, high frequency properties of a product are also deteriorated, such that at the time of mounting the multilayer ceramic capacitor on the circuit board, or the like, the acoustic noise and a ripple voltage may be insufficiently removed.
Patent Document 1 discloses a multilayer ceramic capacitor, but fails to disclose that an increase in ESL of the multilayer ceramic capacitor is suppressed.